With recent improvements in speech processing strategies, a significant number of cochlear implant users are enjoying open set speech performance levels that are higher than the best aided performance of many people with too much residual hearing to be considered candidates for an implant. One possible response to this situation is to relax the requirements for cochlear implant candidacy. Another is to apply the approaches that have been so successful in improving the performance of cochlear implant patients to a new generation of acoustic hearing aids. One way of doing this is to combine multichannel speech processing strategies of proven benefit to cochlear implant users with acoustic synthesis techniques designed to exploit each patient's individual pattern of residual hearing. The goal of this pilot project is to demonstrate the feasibility of custom-fitted, multichannel, acoustic synthesis hearing aids, and to identify future studies that will further their development. Consonant identification tests will be used to assess the effectiveness of various designs. Each of a group of subjects with normal hearing will test devices designed to address a wide range of patterns of residual hearing. Pilot data will be collected for a limited number of subjects with severe hearing impairments. After evaluation with prerecorded synthesized test materials, selected designs will be implemented on wearable real-time digital hardware, and further evaluated with tests of open set word and sentence identification.